Paper by Dr Bivas Rana published in Advanced Quantum Technologies

The article Role of Spin–Orbit Coupling on Ultrafast Spin Dynamics in Nonmagnet/Ferromagnet Heterostructures wirtten by Dr Bivas Rana was published in prestigious journal Advanced Quantum Technologies (98 percentile in the Scopus database, in the category Mathematical Physics ).

https://doi.org/10.1002/qute.202200016

Abstract:

Spin–orbit coupling (SOC), the interaction between spin and orbital angular momentum of electrons, is imperative to control magnetic properties of nonmagnet (NM)/ferromagnet (FM) heterostructures and design energy-efficient and faster spin-based devices. Here, femtosecond pulsed laser-induced time-resolved magneto-optical Kerr effect magnetometry is employed to investigate magnetization dynamics in different NM/Co₂₀Fe₆₀B₂₀ heterostructures, where the NM layer varies as Cu, Ta, W, Pt, Ta/Ru/Ta, and Si/SiO₂ (no underlayer) that differ in SOC strength. It is observed that there is a systematic variation in ultrafast demagnetization time (τ_m), fast remagnetization time (τ_r), and Gilbert damping parameter (α) with the SOC strength of the underlayer and an inverse relationship between α and τ_m, τ_r is established due to the dominant contribution of spin current transport in ultrafast demagnetization and fast remagnetization processes. The spin pumping formalism estimates the effective spin-mixing conductance (G_eff) for different interfaces, which signifies that the high SOC strength of underlayers results in high G_eff indicating more efficient transport of spin current through it. This study suggests that the SOC strength of the NM underlayer plays a significant role in controlling the ultrafast demagnetization process through interfacial spin current transport in a NM/FM heterostructure which can be beneficial for the development of ultrafast spintronics devices.